Inkjet type printers typically employ print cartridges installed in a carriage that is moved transverse the print media. Contemporary disposable inkjet print cartridge typically include a self-contained ink container, a print head including a plurality of inkjet nozzles in combination with the ink container, and a plurality of external electrical contacts for connecting the inkjet nozzles to driver circuitry. Typically in a desktop printer, the entire cartridge must be disposed of when the ink in the container is spent without regard to whether the print head assembly remains functional. As the inkjet technology has improved over the years, the reliability of the print cartridges has improved dramatically. The print head assemblies used in the contemporary disposable inkjet print cartridges are fully operable to their original print quality specifications after printing tens or even hundreds of times more ink than the volume of the self-contained ink container.
Efforts have been pursued in the inkjet industry to extend the lives of the print cartridges in printers to reduce the cost of operation and to reduce the frequency of cartridge replacement for customers, as well as for environmental reasons. Print cartridge life can be extended by merely making the cartridge container larger in size so that it can hold more ink. But this approach adds extra weight on the printer carriage, which moves side to side continuously across the media width for image printing. The extra weight on the carriage causes more mechanical stress to printer structure and demands on larger motor to drive the carriage.
U.S. Pat. No. 5,686,947, to R. A. Murray et al., discloses a wide format inkjet printer which provides a substantially continuous flow of ink to a print cartridge from a large, refillable ink reservoir permanently mounted within the inkjet printer. Flexible tubing, also permanently mounted within the inkjet printer, connects the reservoir to the print cartridge. The off-carriage ink delivery system allows a print cartridge to function for the full cartridge life while eliminating the problems related to the extra weight on the carriage of an on-carriage large ink system. The permanent refillable reservoir provides users with the flexibility of refilling ink without having to stop the printing operation. However, the refilling operation is generally not user friendly and can result in spilling ink.
U.S. Pat. No. 6,033,064 to Pawlowski et al. discloses a replaceable off-carriage ink cartridge, which has an internal bag for holding ink. The internal volume can be pressurized to speed up ink filling from the ink supply cartridge to the print cartridge on the carriage. Another ink cartridge with an internal ink bag is disclosed in U.S. Pat. No. 6,536,888 to Trafton et al. U.S. Pat. No. 6,079,823 by Droege discloses a replaceable ink bottle with a puncturable diaphragm closing the mouth of the bottle. The bottle has a simple structure. The ink in the bottle flows to the print cartridge due to the gravity of the ink.